HK1144671B - Oxygen concentrator - Google Patents

Description

Oxygen concentration device

Technical Field

The present invention relates to an oxygen concentration device for producing oxygen-enriched air for selectively removing nitrogen from raw air using an adsorbent that selectively adsorbs nitrogen molecules rather than oxygen molecules, to supply users.

Background

In recent years, there is a trend toward an increase in patients suffering from respiratory diseases such as asthma, emphysema, and chronic bronchitis, and as one of the most effective treatment methods, oxygen inhalation therapy has been developed in which an oxygen cylinder or an oxygen concentrator for directly separating oxygen-concentrated gas from air is used as a treatment device for oxygen inhalation therapy.

As an oxygen concentrator, a Pressure Swing Adsorption (hereinafter referred to as PSA) type oxygen concentrator is widely used in society, which introduces compressed air into an Adsorption cylinder filled with an adsorbent such as zeolite (zeolite) that selectively adsorbs nitrogen gas by a compressor, selectively removes nitrogen gas from the air, and produces oxygen gas at a high concentration.

The PSA-type oxygen concentrator produces high-concentration oxygen gas from air through the following steps. First, pressurized air is supplied into the adsorption cylinder by a compressor, and nitrogen contained in the air is adsorbed by an adsorbent such as zeolite. The oxygen concentration in the air is raised by selectively adsorbing and removing nitrogen. The high-concentration oxygen obtained as described above is sent to a buffer (product tank) for storing oxygen through a check valve provided to prevent the backflow of oxygen, and stored therein.

On the other hand, the pressure inside the adsorption cylinder is reduced to desorb the nitrogen gas adsorbed in the adsorbent, thereby recovering the adsorption capacity of the adsorbent. In this case, a small amount of concentrated oxygen gas may be supplied into the adsorption cylinder to promote nitrogen desorption.

Thus, by repeating the pressurization and depressurization of the adsorption cylinder using the PSA-type oxygen concentrator, high-concentration oxygen-enriched air having an oxygen concentration of, for example, 95% can be obtained from the air. In recent years, as such a PSA-type oxygen concentrator, a multi-cartridge oxygen concentrator has been used in which a plurality of adsorption cartridges filled with an adsorbent that selectively adsorbs nitrogen gas are simultaneously installed, and the adsorption cartridges are sequentially switched by a rotary valve, thereby improving the oxygen concentration efficiency.

It is known that in the PSA-type oxygen concentrator, the obtained oxygen concentration has a great dependence on the pressure of air compressed by the compressor. Therefore, in order to obtain oxygen of high concentration, it is necessary to increase the compressor capacity in order to increase the pressure of the air supplied to the adsorption cylinder as much as possible. However, the problem arises that the power consumption of the device increases as the supply capacity of the compressor for pressurized air increases.

As a countermeasure for solving the problems of the PSA-type oxygen concentrator, various attempts have been made. Patent document 2 discloses a PSA-type oxygen concentrator that achieves low power consumption by changing the supply capacity of a pressurized air supply device such as a compressor based on the detected value of an oxygen concentration detection device for oxygen to control the oxygen concentration to a constant oxygen concentration.

Patent document 1: japanese patent laid-open publication No. 2006-141896

Patent document 2: japanese patent laid-open publication No. 2007-000340

Patent document 3: japanese laid-open patent publication No. 2002-253675

Disclosure of Invention

Problems to be solved by the invention

In a PSA-type oxygen concentrator using an adsorbent, generally, when the supply amount of raw material air from a pressurized air supply device such as a compressor and the order of adsorption steps are constant, the oxygen concentration of the resulting concentrated oxygen gas changes depending on the ambient (supply air) temperature. According to the characteristics of the adsorbent, when the temperature is high, the nitrogen adsorption amount of the adsorbent is reduced, nitrogen is desorbed and permeated, and the oxygen concentration of the product is reduced. Further, when the temperature is low, the nitrogen adsorption amount of the adsorbent becomes large, but the product oxygen concentration decreases due to insufficient nitrogen desorption caused by a decrease in the adsorption rate.

In recent years, as seen in patent document 1, a method of ensuring a high concentration of oxygen by changing the capacity of a pressurized air supply device such as a compressor based on the ambient temperature has been proposed. However, such a device has a problem of high power consumption and the like because it is necessary to increase the pressure of air introduced into the adsorption cylinder as much as possible and to increase the capacity of a pressurized air supply device such as a compressor.

Patent document 2 describes a PSA-type oxygen concentrator that achieves low power consumption by changing the supply capacity of a pressurized air supply device such as a compressor based on the detected value of an oxygen concentration detection device for oxygen. However, the PSA-type oxygen concentrator using the adsorbent has different adsorption characteristics depending on the ambient temperature, and thus has different supply capacities and response times to the oxygen concentration when the supply capacity of a pressurized air supply device such as a compressor is changed. Therefore, it is necessary to change the control device according to the ambient temperature.

In particular, in a low-temperature environment, since it takes time for the process to be stable at a high temperature, the responsiveness to the oxygen concentration is slow, and it takes time until the product concentration is lowered. When such an apparatus is operated in a low-temperature environment, the stabilization time of the oxygen concentration, i.e., the response time of the oxygen concentration, with respect to the operation of the pressurized air supply device such as a compressor is very slow, and the state where the oxygen concentration is high is often continued when the adsorption process is not stable. Therefore, the capacity of the pressurized air supply facility such as a compressor is reduced to be lower than the originally required raw material air amount in accordance with the detected oxygen concentration. When the process is stabilized, the capacity of the raw material air supply facility is lower than the amount of air originally required, so that the oxygen concentration is rapidly lowered, and there is a risk that the QOL of the user is lowered.

Further, as shown in patent document 3, there has been proposed a device including an oxygen concentration detection means, and controlling a product gas to be generated within a constant oxygen concentration by changing a capacity of a pressurized air supply means such as a compressor based on the detected oxygen concentration. Such a device reduces the capacity of the raw material air supply facility when it is a new product having a high oxygen concentration capacity, thereby reducing the power consumption.

In general, in an oxygen concentrator, when a supply amount of raw material air from a pressurized air supply device such as a compressor is constant, an oxygen concentration of the resulting concentrated oxygen gas as a product changes according to a take-out flow rate, and when the take-out flow rate of the product gas is large, the oxygen concentration decreases, whereas when the take-out flow rate is small, the oxygen concentration of the product gas increases.

A patient using the oxygen concentration device inhales oxygen from the nasal cannula by means of an extension tube or the like connected to the device, and therefore there are the following situations: when sleeping, the nasal cannula or extension tube as an oxygen supply device is crushed by the body of the patient, and the patient cannot inhale the oxygen flow rate that should be inhaled.

In the apparatus described in patent document 3, when the product flow rate is decreased by squeezing the pipe or the like, the oxygen concentration is temporarily increased, and it is necessary to control the capacity of the pressurized air supply device such as a compressor to be decreased. In this state, when the squeezing of the pipe is resumed and the product flow rate is resumed, the pressurized air supply device such as a compressor is rather insufficient in capacity, and the oxygen concentration is lowered, so that there is a possibility that an abnormality alarm for the oxygen concentration, which is originally unnecessary, is issued.

Further, a flow sensor for detecting an oxygen flow rate is mounted in the apparatus as described in patent document 3, and when the flow rate sensor cannot normally detect the flow rate or when the flow rate adjustment by the flow rate adjustment device cannot be normally performed in the case where the oxygen flow rate is adjusted by using a flow rate adjustment device such as a proportional valve based on the detection value of the flow rate sensor, there is a possibility that the oxygen supply amount becomes larger than the oxygen flow rate that the patient should originally inhale. Since the oxygen concentration decreases as the flow rate of the extracted oxygen increases, control is performed to increase the capacity of a pressurized air supply device such as a compressor in order to correct this. When the product flow returns to normal, the power consumption is too high, and the economic burden of the patient may become large.

Means for solving the problems

The invention provides an oxygen concentrator which can reduce the power consumption by reducing the capacity of a raw material air supply device, and stably supplies high-concentration oxygen to a patient with low power consumption regardless of the increase and decrease of the ambient temperature and/or a constant oxygen flow.

Further, the present inventors have found that, by mounting an oxygen flow rate detection sensor in addition to controlling the supply capacity of the raw material air supply means based on the detected value of the oxygen concentration, and performing control not to allow a change in the supply capacity of the raw material air supply means when the detected value of the flow rate deviates from a predetermined set value, the amount of raw material air does not change even if the flow rate of oxygen decreases due to, for example, pipe squeezing, and therefore the oxygen concentration can be maintained when the product flow rate returns to normal.

Further, it has been found that by performing the same control as described above, for example, when the flow sensor cannot normally detect or the flow adjustment by the flow adjusting means cannot normally be performed, even if the oxygen flow rate becomes larger than the oxygen flow rate that the patient should originally inhale, the amount of the raw material air does not change, and therefore, when the product flow rate returns to normal, it is possible to prevent high power consumption due to the capability of setting the pressurized air supplying means beyond necessity.

In the oxygen concentrator having such a control device, the predetermined threshold value of the flow rate sensor detection value may be individually assigned by a set value of the flow rate setting device of the oxygen concentrator, or may not be assigned by the set flow rate.

However, as described in international standard ISO8359 and japanese industrial standard JIST7209, a flow rate sensor generally mounted on a medical oxygen concentrator is preferably set to ± 10% of a set flow rate as a predetermined threshold value of a flow rate sensor detection value in order to achieve accuracy of about ± 10% of the set flow rate, and the ability to change a pressurized air supply device is not allowed for a flow rate detection value of + 10% or more or-10% or less.

The oxygen concentration sensor used in the oxygen concentration device is generally of a zirconia type or an ultrasonic type, and similarly, the flow sensor is generally of an ultrasonic type or a hot-wire type.

Namely, the present invention is as follows.

(1) A pressure swing adsorption type oxygen concentrator comprising an adsorption bed packed with an adsorbent which selectively adsorbs nitrogen in comparison with oxygen, and a pressurized air supply means for supplying pressurized air to the adsorption bed, wherein nitrogen in feed air is removed by adsorption to produce unadsorbed oxygen, and oxygen is supplied at a predetermined flow rate by a flow rate setting means, characterized by comprising

An oxygen concentration sensor for detecting the concentration of oxygen generated by the oxygen concentration device, and

a temperature sensor for measuring the temperature of the environment,

the oxygen concentrator is provided with a temperature-dependent control means for performing control of increasing/decreasing the supply air volume of the pressurized air supply means based on a detected value of the oxygen concentration to maintain the oxygen concentration at a predetermined concentration, and for performing control of the supply air volume of the pressurized air supply means based on the detected value of the temperature sensor when the detected value of the temperature sensor deviates from a predetermined threshold value.

(2) The oxygen concentrator according to (1), wherein the temperature-dependent control means performs control not to allow the reduction of the supply air volume of the pressurized air supply means when the temperature sensor detects a value less than a predetermined lower limit value of the threshold temperature during the start-up of the oxygen concentrator.

(3) The oxygen concentrator according to (1), wherein the temperature-dependent control means performs control not to permit reduction of the supply air volume of the pressurized air supply means when the temperature sensor detects a value less than a predetermined lower limit value of the threshold temperature and the supply air volume is lower than a predetermined air volume during startup of the oxygen concentrator.

(4) The oxygen concentrator according to any one of (1) to (3), wherein the temperature-dependent control means controls the supply airflow rate of the pressurized air supply means to be higher than the supply airflow rate corresponding to the detection value of the oxygen concentration regardless of the detection value of the oxygen concentration sensor when the temperature sensor detects a value less than the lower limit temperature value of the threshold at the time of starting the apparatus.

(5) The oxygen concentrator according to any one of (2) to (4), wherein the lower limit temperature is 5 ℃.

(6) An oxygen concentrator comprising an adsorption bed packed with an adsorbent that selectively adsorbs nitrogen in comparison with oxygen, and a pressurized air supply means for supplying pressurized air to the adsorption bed, wherein nitrogen in raw air is adsorbed and removed to generate unadsorbed oxygen, and oxygen is supplied at a predetermined flow rate by a flow rate setting means, the oxygen concentrator comprising

An oxygen concentration sensor for detecting the concentration of the generated oxygen, and

a flow sensor for measuring the flow rate of oxygen,

the oxygen concentrator is provided with a flow rate dependency control means for performing control for increasing/decreasing the supply air volume of the pressurized air supply means based on the detected value of the oxygen concentration to maintain the oxygen concentration at a predetermined concentration, and for performing control for not allowing the supply air volume of the pressurized air supply means to be changed when the detected value of the flow rate sensor deviates from a predetermined range.

(7) The oxygen concentrator according to (6), wherein the threshold value of the detection value of the flow rate sensor is a value that is individually assigned according to the set value of the flow rate setting means or is assigned not according to the set flow rate value.

(8) The oxygen concentrator according to (7), wherein the flow rate dependency control means performs control not to allow the change of the supply air volume of the pressurized air supply means regardless of the detection value of the oxygen concentration sensor when the detection value of the flow rate sensor is + 10% or more or-10% or less of the setting value of the flow rate setting means.

(9) The oxygen concentrator according to any one of (6) to (8), wherein the flow sensor is an ultrasonic or hot-wire flow sensor.

(10) An oxygen concentrator comprising an adsorption bed packed with an adsorbent that selectively adsorbs nitrogen in comparison with oxygen, and a pressurized air supply means for supplying pressurized air to the adsorption bed, wherein nitrogen in raw air is adsorbed and removed to generate unadsorbed oxygen, and oxygen is supplied at a predetermined flow rate by a flow rate setting means, the oxygen concentrator comprising

An oxygen concentration sensor for detecting the concentration of oxygen generated by the oxygen concentration device,

Temperature sensor for measuring ambient temperature, and

a flow sensor for measuring the flow rate of oxygen,

the oxygen concentrator comprises the following control devices: the device performs a temperature-dependent control of increasing and decreasing the supply air volume of the pressurized air supply device based on the detected value of oxygen concentration to maintain the oxygen concentration at a predetermined concentration, and a flow rate-dependent control of not allowing the supply air volume of the pressurized air supply device to be changed when the detected value of the flow rate sensor deviates from a predetermined range, based on the detected value of the temperature sensor.

(11) The oxygen concentrator according to (10), wherein the control device performs control to disallow reduction of the supply air volume of the pressurized air supply device when the temperature sensor detects that the temperature sensor does not reach the predetermined lower limit value of the threshold temperature and the supply air volume is lower than a predetermined air volume during startup of the oxygen concentrator.

(12) The oxygen concentrator according to (10) or (11), wherein the control means controls the supply air volume of the pressurized air supply means to be supplied at a value higher than the supply air volume corresponding to the detection value of the oxygen concentration, regardless of the detection value of the oxygen concentration sensor, when the temperature sensor detects a value lower than the lower limit temperature value of the threshold at the time of starting the apparatus.

(13) The oxygen concentrator according to any one of (1) to (12), wherein the oxygen concentration sensor is a zirconia-type or ultrasonic-type oxygen concentration sensor.

Effects of the invention

The present invention is an oxygen concentrator which performs control for increasing and decreasing the supply air volume of a pressurized air supply device to maintain a predetermined concentration based on the detection value of an oxygen concentration sensor for detecting the oxygen concentration, wherein a temperature sensor for measuring the gas temperature (ambient temperature) is provided, the reduction of the supply air volume of the pressurized air supply device is not allowed based on the temperature detection value, and the supply is performed at a value higher than the supply air volume corresponding to the oxygen concentration detection value at the time of start-up, thereby preventing the excessive reduction of the supply air volume at the time of low temperature and stably supplying high-concentration oxygen to a patient regardless of the ambient temperature.

The present invention is also an oxygen concentrator that performs control for increasing or decreasing the supply air volume of a pressurized air supply device based on the detection value of an oxygen concentration sensor for detecting the oxygen concentration so as to maintain a predetermined concentration, the oxygen concentrator including a flow sensor for measuring the oxygen flow volume, and performing control for not allowing the increase or decrease of the supply volume of the pressurized air supply device based on the flow volume detection value, thereby preventing the decrease of the oxygen concentration or the increase in power consumption beyond necessity even when a pipe is squeezed or a flow rate detector or a flow rate regulator does not function properly.

Drawings

FIG. 1 is a schematic view showing the constitution of an oxygen concentrator of the present invention

FIG. 2 control description of the invention

FIG. 3 is a schematic view showing the structure of an oxygen concentrator according to another embodiment of the present invention.

Description of the symbols

1. Oxygen concentration device

3. User (patient)

101. External air intake filter

103. Compressor with a compressor housing having a plurality of compressor blades

104. Switching valve

105. Adsorption cylinder

106. Pressure equalizing valve

107. Check valve

108. Product tank

109. Pressure regulating valve

110. Flow rate setting device

111. Filter

301. Oxygen concentration sensor

302. Flow sensor

303. Temperature sensor

401. Control device

402. Recording apparatus

Detailed Description

An oxygen concentrator as an embodiment of the present invention will be described with reference to the drawings. Furthermore, the present invention is not limited in any sense by these embodiments.

Fig. 1 is a schematic view illustrating the apparatus configuration of a PSA-type oxygen concentrator according to an embodiment of the present invention. In fig. 1, 1 denotes an oxygen concentrator, and 3 denotes a user (patient) who inhales humidified oxygen-enriched air. The PSA-type oxygen concentrator 1 includes an outside air intake filter 101, a compressor 103 as a pressurized air supply device, a switching valve 104, an adsorption cylinder 105, a pressure equalizing valve 106, a check valve 107, a product tank 108, a pressure regulating valve 109, a flow rate setting device 110, and a filter 111. Oxygen-enriched air in which oxygen is concentrated can be produced from the raw air taken in from the outside.

First, the raw material air taken in from the outside is taken in from an air intake port provided with an outside air intake filter 101 or the like for removing foreign matter such as dust. In this case, the normal air contains about 21% of oxygen, about 77% of nitrogen, 0.8% of argon, water vapor and other gases 1.2%. In the apparatus, only oxygen required as a respiratory gas is concentrated and taken out.

The oxygen gas is taken out by sequentially switching the target adsorption cylinder 105 by the switching valve 104 with respect to the adsorption cylinder 105 filled with an adsorbent such as zeolite which selectively adsorbs nitrogen molecules from the raw air as compared with oxygen molecules, and by supplying the raw air under pressure by the compressor 103, about 77% of the nitrogen gas contained in the raw air is selectively adsorbed and removed in the adsorption cylinder 105.

The adsorption cylinder 105 is formed of a cylindrical container filled with the adsorbent, and a multi-cylinder type having three or more cylinders is generally used in addition to a single-cylinder type and a double-cylinder type, but in order to continuously and efficiently produce oxygen-enriched air from raw air, it is preferable to use the adsorption cylinder 105 having a multi-cylinder type. In addition, as the compressor 103, a rotary air compressor such as a screw type, a rotary type, or a scroll type may be used in addition to the swing type air compressor. The power supply of the motor for driving the compressor 103 may be either ac or dc.

The oxygen-enriched air containing oxygen not adsorbed by the adsorption cylinder 105 as a main component flows into the product tank 108 through the check valve 107 provided so as not to flow backward into the adsorption cylinder 105.

In order to adsorb nitrogen again from the newly introduced raw material air, the nitrogen adsorbed by the adsorbent filled in the adsorption cylinder 105 needs to be desorbed from the adsorbent. Therefore, by switching the valve 104 from the pressurized state by the compressor 103 to a depressurized state (for example, an atmospheric pressure state or a negative pressure state), the adsorbed nitrogen gas is desorbed to regenerate the adsorbent. In the desorption step, in order to improve the desorption efficiency, oxygen-enriched air may be caused to flow back as a purge gas from the product end side of the adsorption cylinder in the adsorption step through the pressure equalizing valve 106.

Oxygen-enriched air is prepared from the feed air and stored in the product tank 108. The oxygen-enriched air stored in the product tank 108 contains oxygen of high concentration such as 95%, and is supplied to the humidifier 201 through the pressure regulating valve 109, the flow rate setting device 110, or the like while controlling the supply flow rate and pressure thereof, so that humidified oxygen-enriched air is supplied to the patient. The flow rate setting device 110 may use a flow rate control valve such as a regulator valve, in addition to an orifice type flow rate setter.

The set value of the flow rate setting means 110 for setting the supply flow rate of the oxygen-enriched air, the concentration value of the oxygen concentration sensor 301, and the actual oxygen flow rate value of the flow rate sensor 302 are detected, and the detection results are stored in the recording means 402 such as a memory to monitor the operation state, and the control means 401 controls the number of revolutions of the motor (motor) of the compressor 103 to control the supply amount of the raw material air and further controls the switching timing of the adsorption/desorption by controlling the switching valve 104 in order to adjust the oxygen generation amount based on the detection results. As the oxygen concentration sensor, a zirconia type oxygen sensor or an ultrasonic type oxygen sensor can be used. As the flow sensor, a hot wire mass flow meter (mass flow meter) or an ultrasonic flow sensor may be used. The ultrasonic sensor can measure the oxygen concentration and the oxygen flow rate with one sensor, and is preferable in terms of miniaturization and reduction in the number of components.

The present invention performs control of increasing or decreasing the supply air volume of a pressurized air supply device to maintain a predetermined concentration based on the detection value of an oxygen concentration sensor for detecting the oxygen concentration, and also includes a temperature sensor 303 for measuring the temperature of the device, and the control device is changed based on the measurement value of the temperature sensor. In this specification, a control device that performs control based on a measured value of a temperature sensor is also referred to as a temperature-dependent control device.

When the detected value of the temperature sensor is detected to be less than a predetermined lower limit value (threshold value) of temperature, control is performed to prevent the reduction of the supply air volume of the pressurized air supply equipment, and when the detected value of the temperature sensor is detected to be less than the lower limit value of temperature at the time of starting the device, control is performed to supply the supply air volume of the pressurized air supply equipment at a value of the supply air volume higher than the value corresponding to the detected value of the oxygen concentration regardless of the detected value of the oxygen concentration sensor, thereby preventing the product oxygen concentration from reaching a predetermined concentration.

That is, when the detected value of the temperature sensor is detected to be less than the predetermined lower temperature limit value, the control for reducing the supply air volume of the pressurized air supply device such as the compressor is not performed. In this case, in addition to the value at which the lower temperature limit value is not detected, when the supply air volume is lower than the predetermined air volume, if the control that does not allow the reduction of the supply air volume of the pressurized air supply equipment is performed, it is preferable because the control is more accurate. The case where the supply air volume is lower than the predetermined air volume means a case where the supply air volume is lower than the supply air volume when the oxygen concentration cannot be secured to the predetermined concentration in the environment below the predetermined temperature lower limit value. That is, the predetermined air volume means the minimum supply air volume in which the oxygen concentration is a predetermined concentration can be secured in an environment where the temperature is less than the predetermined lower limit value (5 ℃ in fig. 2) as indicated by the broken line in fig. 2.

Specifically, the region in fig. 2B is a case where the temperature lower limit value is detected and the supplied air volume is lower than the predetermined air volume. Fig. 2 is a diagram illustrating control according to temperature of the present invention. In fig. 2, the predetermined air volume is set to be the same as the supply air volume at the time of startup, when the temperature is lower than the lower limit value. The predetermined air volume varies depending on the predetermined lower temperature limit and the predetermined oxygen concentration, and is, for example, 1.05 to 1.2 times the supply air volume at the time of startup at a temperature not lower than the lower temperature limit. When it is detected that the detected value of the temperature sensor is less than the predetermined lower limit temperature value and the supply air volume is higher than the predetermined air volume, control is performed to reduce the supply air volume of the pressurized air supply device such as the compressor. Specifically, the region a of fig. 2 is below the lower temperature limit. The area a is an area hatched in fig. 2.

In addition, in the oxygen concentrator using the compressor as the pressurized air supply device, when the temperature sensor detects a value less than the predetermined lower limit temperature value at the time of starting the device, the piston ring of the compressor is hardened, and therefore, it is effective to increase the supply air volume in advance to promote the softening of the piston ring. Therefore, when the temperature sensor detects a value less than the predetermined lower limit temperature value at the time of starting the apparatus, control is performed to increase the supply air volume of the pressurized air supply device such as the compressor and supply the air at a supply air volume value higher than the value corresponding to the detected concentration value. The high value of the supply air volume differs depending on each set flow rate (prescribed flow rate), and may be set in advance to be 1.05 to 1.2 times the supply volume equal to or higher than the lower temperature limit, for example.

As the control of increasing or decreasing the supply air volume of the pressurized air supply facility based on the detection value of the oxygen concentration sensor according to the present invention, control methods such as p (proport) control in which the input value is operated in proportion to the deviation from the detection value, i (integral) control in which the input value is operated in proportion to the integral value of the deviation, and PI control in which these are combined are preferably used for the target value of the oxygen concentration.

In the case of the oxygen concentrator, it is desirable that the response time of the oxygen concentration, which is the steady time for the operation of the pressurized air supply equipment, be set to 5 to 10 minutes, and in the present invention, the increase or decrease in the supply air volume of the pressurized air supply equipment is determined from the detected value of the oxygen concentration every 5 to 10 minutes of the steady time.

At low temperatures, the rate of adsorption and desorption of the adsorbent is reduced, and the amount of nitrogen desorbed in the desorption step is reduced, so that the amount of nitrogen adsorbed increases gradually. Therefore, the response of the decrease in the oxygen concentration is slowed by the increase/decrease control of the supply air volume of the pressurized air supply equipment, particularly the decrease control of the supply air volume.

When the response time of the oxygen concentration is slow, there is a possibility that the control is excessive. In the oxygen concentrator using the adsorbent, the characteristics of the adsorbent are different depending on the temperature, and when the ambient temperature is low and the supply air volume is reduced, it is confirmed that the response time of the oxygen concentration with respect to the supply air volume is slow.

The response time of the oxygen concentration to the supplied air volume becomes slow to a temperature at which the control is excessive, and varies depending on the adsorption step and the amount of the adsorbent. In the case of the present invention, under an environment of 5 ℃, the above-described excessive control was not observed and the oxygen concentration was significantly reduced, that is, it was confirmed that the responsiveness of the oxygen concentration corresponding to the supplied air amount was sufficient. Therefore, the lower limit of the temperature for the control of reducing the supply air volume of the pressurized air supply device by the detected oxygen concentration value may be 5 ℃ or higher. In the present invention, the lower limit temperature value of the control for reducing the supply air volume of the pressurized air supply device is set to 5 ℃.

When the temperature of less than 5 ℃ is detected during the start-up and the supply air volume is lower than a predetermined air volume, the control for reducing the supply air volume of the pressurized air supply device based on the detected value of the oxygen concentration is stopped even if the oxygen concentration is higher than the predetermined value. On the other hand, when the oxygen concentration is lower than the predetermined value, control for increasing the supply air volume of the pressurized air supply device based on the detected value of the oxygen concentration is maintained. When the temperature is maintained below 5 ℃, the control is performed, and when the detection value of the temperature sensor exceeds 5 ℃, the control is switched to the control of the supply air volume of the pressurized air supply device based on the detection value of the normal oxygen concentration.

When the oxygen concentrator is started, the air supply rate of the air supply means is controlled so that the air supply rate can be maintained at a predetermined product concentration at an ambient temperature of-5 ℃ which is the lower limit of the operation guaranteed temperature of the present invention when the ambient temperature sensor detects less than 5 ℃, and the supply is controlled to a value higher than the supplied air supply rate so that the concentration is prevented from being lowered due to excessive control when the temperature sensor detects less than 5 ℃.

Further, when the temperature sensor detects 5 ℃ or higher, the control for allowing the air volume supplied from the air supply device to be reduced to the air volume supplied according to the oxygen concentration is carried out without the fear of the excessive control, and the power consumption of the apparatus is reduced.

When the temperature sensor detects 5 ℃ or higher at the time of startup, and thereafter detects less than 5 ℃, and the supply air volume is lower than a predetermined air volume, control is performed to prevent the supply air volume from decreasing when the temperature sensor detects less than 5 ℃.

Another aspect of the present invention is an oxygen concentrator that performs control for increasing or decreasing the supply air volume of a pressurized air supply device based on a detection value of an oxygen concentration sensor for detecting the oxygen concentration so as to maintain a predetermined concentration, includes a flow sensor for measuring the supply flow rate of oxygen, and performs control for not allowing the increase or decrease of the supply air volume of the pressurized air supply device when the flow rate detection value deviates from a flow rate range determined based on a set flow rate. In this case, since the temperature sensor is not essential, an embodiment excluding the temperature sensor from fig. 1 is shown in fig. 3. In this specification, a control device that performs control based on a flow rate measurement value is also referred to as a flow rate-dependent control device.

As the control for increasing or decreasing the supply air volume of the pressurized air supply facility based on the detection value of the oxygen concentration sensor, control methods such as p (proportional) control in which the operation input value is proportional to the deviation from the detection value, i (integral) control in which the operation input value is proportional to the integral value of the deviation, and PI control in which these are combined are preferably used for the target value of the oxygen concentration.

In the present invention, it is effective to perform control judgment of the pressurized air supply equipment every 5 to 10 minutes of the stabilization time, and particularly, when the oxygen flow rate is reduced for a long time due to pipe squeezing or the like during sleep or the like, the oxygen concentration is increased, and the supply capacity of the pressurized air supply equipment is reduced, if the capacity of the pressurized air supply equipment is reduced within a period of 5 to 10 minutes, the supply capacity of the pressurized air supply equipment may be excessively reduced, and even if the oxygen flow rate is restored to normal, an oxygen concentration alarm may be issued even if the original apparatus is not in trouble during the time of restoration to the capacity of the pressurized air supply equipment necessary for the normal oxygen flow rate.

Therefore, in the present invention, not only the oxygen concentration is detected every 5 to 10 minutes of the stabilization time, but also whether or not the supply air volume of the pressurized air supply facility can be increased or decreased is determined based on the detected value of the oxygen flow rate, whereby it is possible to generate an unnecessary oxygen concentration alarm even if the oxygen flow rate is decreased or increased by the eliminating means, regardless of the increase or decrease of the oxygen concentration, and it is possible to suppress an unnecessary increase in power consumption due to an increase in the capacity of the pressurized air supply facility.

In addition, when the accuracy of the flow rate sensor required by the oxygen concentration device is taken into consideration, the possibility that a state deviating from ± 10% of the set flow rate as the oxygen flow rate is an abnormal state is high, and in the present invention, when the device is returned to the normal state, the desired oxygen concentration and oxygen flow rate can be quickly realized.

In addition, as another embodiment of the present invention, there is an oxygen concentrator which performs control for increasing or decreasing the supply air volume of a pressurized air supply device based on a detection value of an oxygen concentration sensor for detecting the oxygen concentration so as to maintain a predetermined concentration, includes a temperature sensor for measuring the temperature of the oxygen concentrator, changes a control device based on a measurement value of the temperature sensor, includes a flow sensor for measuring the supply flow rate of oxygen, and performs control for not allowing the increase or decrease of the supply amount of the pressurized air supply device based on a detection value of the flow rate.

The oxygen concentration device corresponds to, for example, a device similar to fig. 1 having an oxygen concentration sensor, a flow rate sensor, and a temperature sensor.

That is, it is preferable that the detection value of the temperature sensor is detected to be a value lower than a predetermined lower limit temperature, and when the supply air volume of the pressurized air supply facility is further lower than a predetermined supply air volume, or when the supply flow rate of oxygen deviates from a flow rate range determined based on the set flow rate, control is performed such that reduction of the supply air volume of the pressurized air supply facility is not permitted, and when the supply flow rate of oxygen deviates from the flow rate range determined based on the set flow rate, control is performed such that increase of the supply air volume of the pressurized air supply facility is not permitted, and when the apparatus is started, the value lower than the lower limit temperature is detected, and control is performed such that the supply air volume is supplied at a value higher than the supply air volume corresponding to the detection value of the oxygen concentration.

In this embodiment, the control according to the temperature and the control according to the flow rate are combined, and redundant description is omitted. For example, the following items and the like are the same as described above: setting the lower limit value of the temperature to be 5 ℃; individually distributing a threshold value of a detection value of the flow sensor according to a set value of the flow setting device or not according to a flow set value; when the detected value of the flow rate sensor is more than or equal to + 10% or less than-10% of the set value of the flow rate setting device, control is performed to disallow the change of the supply air volume of the pressurized air supply device regardless of the detected value of the oxygen concentration sensor.

According to the present invention, a desired oxygen concentration can be stably provided.

Claims (8)

1. A pressure swing adsorption type oxygen concentrator comprising an adsorption bed packed with an adsorbent which selectively adsorbs nitrogen in comparison with oxygen, and a pressurized air supply means for supplying pressurized air to the adsorption bed, wherein nitrogen in feed air is removed by adsorption to produce unadsorbed oxygen, and oxygen is supplied at a predetermined flow rate by a flow rate setting means, characterized by comprising

An oxygen concentration sensor for detecting the concentration of oxygen generated by the oxygen concentration device, and

a temperature sensor for measuring the temperature of the environment,

the oxygen concentrator is provided with a temperature-dependent control means for controlling the supply air volume of the pressurized air supply means so as to increase or decrease the supply air volume of the pressurized air supply means based on a detected value of the oxygen concentration to maintain the oxygen concentration at a predetermined concentration, and for controlling the supply air volume of the pressurized air supply means based on the detected value of the temperature sensor when the detected value of the temperature sensor deviates from a predetermined threshold value,

the temperature-dependent control means is a control means for performing control not to permit a reduction in the supply air volume of the pressurized air supply means regardless of the detection value of the oxygen concentration sensor when the temperature sensor detects a value less than a predetermined lower limit value of the threshold temperature during the start-up of the oxygen concentrator.

2. A pressure swing adsorption type oxygen concentrator comprising an adsorption bed packed with an adsorbent which selectively adsorbs nitrogen in comparison with oxygen, and a pressurized air supply means for supplying pressurized air to the adsorption bed, wherein nitrogen in feed air is removed by adsorption to produce unadsorbed oxygen, and oxygen is supplied at a predetermined flow rate by a flow rate setting means, characterized by comprising

An oxygen concentration sensor for detecting the concentration of oxygen generated by the oxygen concentration device, and

a temperature sensor for measuring the temperature of the environment,

the oxygen concentrator is provided with a temperature-dependent control means for controlling the supply air volume of the pressurized air supply means so as to increase or decrease the supply air volume of the pressurized air supply means based on a detected value of the oxygen concentration to maintain the oxygen concentration at a predetermined concentration, and for controlling the supply air volume of the pressurized air supply means based on the detected value of the temperature sensor when the detected value of the temperature sensor deviates from a predetermined threshold value,

the temperature-dependent control means is a control means for performing control not to permit reduction of the supply air volume of the pressurized air supply means when the temperature sensor detects a value less than a predetermined lower limit value of the threshold temperature and the supply air volume is lower than a predetermined air volume during startup of the oxygen concentrator.

3. The oxygen concentrator according to claim 1 or 2, wherein the temperature-dependent control means controls the supply airflow rate of the pressurized air supply means to be higher than the supply airflow rate corresponding to the detected value of the oxygen concentration, regardless of the detected value of the oxygen concentration sensor, when the temperature sensor detects a value less than the lower limit of the threshold temperature at the time of starting the apparatus.

4. Oxygen concentrator according to claim 1 or 2, wherein the lower temperature limit is 5 ℃.

5. Oxygen concentrator according to claim 3 wherein the lower temperature limit is 5 ℃.

6. An oxygen concentrator comprising an adsorption bed packed with an adsorbent that selectively adsorbs nitrogen in comparison with oxygen, and a pressurized air supply means for supplying pressurized air to the adsorption bed, wherein nitrogen in raw air is adsorbed and removed to generate unadsorbed oxygen, and oxygen is supplied at a predetermined flow rate by a flow rate setting means, the oxygen concentrator comprising

An oxygen concentration sensor for detecting the concentration of oxygen generated by the oxygen concentration device,

Temperature sensor for measuring ambient temperature, and

a flow sensor for measuring the flow rate of oxygen,

the oxygen concentrator comprises the following control devices: the control device performs temperature-dependent control for increasing and decreasing the supply air volume of the pressurized air supply device based on a detected value of the oxygen concentration to maintain the oxygen concentration at a predetermined concentration, and performs control for controlling the supply air volume of the pressurized air supply device based on the detected value of the temperature sensor when the detected value of the temperature sensor deviates from a predetermined threshold value, and flow rate-dependent control for not allowing the supply air volume of the pressurized air supply device to be changed when the detected value of the flow rate sensor deviates from a predetermined range.

7. The oxygen concentrator according to claim 6, wherein the control means performs control to prohibit reduction of the supply air volume of the pressurized air supply means when the temperature sensor detects that the temperature sensor does not reach the lower limit value of the predetermined threshold temperature and the supply air volume is lower than a predetermined air volume during startup of the oxygen concentrator.

8. The oxygen concentrator according to claim 6 or 7, wherein the control means controls the supply air volume of the pressurized air supply means to be supplied at a value higher than the supply air volume corresponding to the detection value of the oxygen concentration, regardless of the detection value of the oxygen concentration sensor, when the temperature sensor detects a value lower than the lower limit temperature value of the threshold at the time of starting the apparatus.